1. Field of the Invention
This invention relates to a culture observation apparatus that is used for observing cultured cells while culturing the cells.
2. Description of the Related Art
In the field of biological research, various experiments have been conducted with the use of cultured cells for the study of dynamic changes in living organisms. The cultured cells are placed in a carbon dioxide incubator that is kept at an inner temperature of 37° C., a carbon dioxide gas concentration of 5%, and a humidity of 100%, together with a liquid referred to as a culture medium made from bovine serum or the like, so that the activities of the cultured cells are maintained. Moreover, observation apparatuses, which allow observation while the activities of the cultured cells are maintained with the use of a microscope equipped with functions of the carbon dioxide incubator, have been commercially available.
Cultured cells and a culture medium are generally cultured in a dish that is made of plastic or glass and has a cylindrical form in its outer shape or a petri dish which is available in various shapes.
Some experiments using such cultured cells last a long period of time, in particular, experiments on cell lineage, in which changes in specific cells are traced, is carried out over a long period of time.
The culture medium, however, needs to be changed once approximately every three days. Hence, the long-term observation of a specific cell necessarily accompanies the exchange of culture mediums; which is carried out on a clean bench or the like after the removal of the container containing cultured cells from the microscope.
A shifting section between the microscope and the clean bench and the inside of the clean bench are rarely kept at 37° C. corresponding to the temperature of the culture space inside the carbon dioxide incubator, and normally set to 20 to 25° C. which allow people to work comfortably. Hence, during the culture medium exchanging operation for about 5 minutes, the temperature of the container housing the cultured cells tends to drop to cause damages on the cultured cells inside the container.